Humidity control for enclosure

ABSTRACT

Aspects of this disclosure are directed to methods, apparatuses and approaches involving the use of a moisture absorbing material (e.g., desiccant) to control moisture. As may be implemented consistent with one or more embodiments, moisture is removed from an environmental control module that includes a desiccant material contained within a package. Liquid is deposited inside the package and sealed with the desiccant in the package.

BACKGROUND

Various types of circuitry and mechanical components benefit fromoperation in a controlled environment. For instance, temperature,humidity, and chemical interaction may affect electronic and/ormechanical devices. Controlling an environment, however, can bedifficult or expensive with regard to manufacturing and long-term use.Further, failure to properly control an environment can adversely affectthe performance or lifetime of various components.

One type of component that is susceptible to issues relating to itsenvironment is a disk drive, which is used for data storage in modernelectronic products ranging from digital cameras to computer systems andnetworks. A disk drive may include a mechanical portion, or head diskassembly (HDA), and electronics in the form of a printed circuit boardassembly (PCBA), mounted to an outer surface of the HDA. The PCBAcontrols HDA functions and provides an interface between the disk driveand its host. An HDA includes moving parts such as one or more magneticdisks affixed to a spindle motor assembly for rotation at a constantspeed, an actuator assembly supporting an array of read/write heads thattraverse generally concentric data tracks radially spaced across thedisk surfaces and a voice coil motor (VCM) providing rotational motionto the actuator assembly. In operation, the magnetic-recording diskrapidly rotates by the spindle motor to access (read and/or write) thedata stored on the disk.

The above challenges can result in issues relating to manufacturing,implementation and longevity for disk drives and a variety of othercomponents.

SUMMARY

Various example embodiments are directed to apparatuses and/or methodsthat mitigate issues relating to humidity and other exposure ofelectrical and/or mechanical components. As may be implemented inaccordance with one or more embodiments, a package is provided with adesiccant therein, and having a liquid sealed within the package alongwith the desiccant. The desiccant absorbs the liquid and operates withthe package to provide moisture control upon the opening of a passagewayinto the package.

In accordance with one or more embodiments, a method involves removingmoisture from an environmental control module having a package and adesiccant material contained within the package. A liquid is depositedinside the package, and is sealed along with the desiccant in thepackage.

Other embodiments are directed to an apparatus, as may be implementedconsistent with methods as characterized herein. In one or more suchembodiments, an apparatus includes a package, a desiccant material andliquid contained within the package, and a seal that seals the liquidand desiccant material in the package. The seal operates with thepackage, desiccant material and liquid to, upon opening of a passagethrough the seal, maintain a humidity level within an enclosureenvironment in which the package resides. For instance, humid gas may bepassed between an interior region of the package and an enclosureenvironment in which the package resides, via the passage.

The above discussion/summary is not intended to describe each embodimentor every implementation of the present disclosure. The figures anddetailed description that follow also exemplify various embodiments.

BRIEF DESCRIPTION OF THE FIGURES

Various example embodiments may be more completely understood inconsideration of the following detailed description in connection withthe accompanying drawings, in which:

FIG. 1 shows a process for configuring an environment control modulestructure, consistent with various aspects of the present disclosure;

FIG. 2 shows a cross-sectional side view illustrating an environmentcontrol module structure, consistent with various aspects of the presentdisclosure;

FIG. 3 shows a cross-sectional side view illustrating an environmentalcontrol module structure and seal, consistent with various aspects ofthe present disclosure;

FIG. 4 shows a cross-sectional side view illustrating an exampleapparatus, consistent with various aspects of the present disclosure;

FIG. 5 shows a graph of relative humidity in an enclosure maintained byenvironmental control modules with various initial moisture charges,consistent with various aspects of the present disclosure;

FIG. 6 shows a graph of water absorption by various materials atdifferent relative humidity levels, consistent with various aspects ofthe present disclosure;

FIG. 7 shows a partial exploded perspective view of an exampleenvironmental control module, consistent with various aspects of thepresent disclosure;

FIG. 8 shows a partial exploded perspective view of an example seal foruse with an environmental control module, consistent with variousaspects of the present disclosure;

FIGS. 9A and 9B show a perspective and cross-sectional view of theenvironmental control module of FIG. 7 with an unsealed opening;

FIGS. 10A and 10B show a perspective and cross-sectional view of theseal of FIG. 8 applied to the environmental control module of FIG. 7;and

FIG. 11 shows a partial exploded perspective view illustrating a diskdrive enclosure, consistent with various aspects of the presentdisclosure.

While the disclosure is amenable to various modifications andalternative forms, specifics thereof have been shown by way of examplein the drawings and will be described in detail. It should beunderstood, however, that the intention is not to limit the disclosureto the particular embodiments described. On the contrary, the intentionis to cover all modifications, equivalents, and alternatives fallingwithin the scope of the disclosure including aspects defined in theclaims. In addition, the term “example” as used throughout thisapplication is only by way of illustration, and not limitation.

DETAILED DESCRIPTION

Aspects of the present disclosure are believed to be applicable to avariety of different types of devices, systems and arrangementsinvolving long-term use of enclosed electronic and/or mechanicaldevices. Specific embodiments of the present disclosure are believed tobe particularly beneficial to a disk drive apparatus including complexmoving mechanisms such as spindle motors and HDAs as described above.While the present disclosure is not necessarily so limited, variousaspects of the disclosure may be appreciated through a discussion ofexamples using this context.

Various aspects of the present disclosure are directed towardmaintenance of environmental conditions within an enclosure housingelectronic and/or mechanical components. Electronic and/or mechanicalcomponents are often contained within an enclosure that protects thecomponents from particulates and other environment-related contaminantsthat may shorten life span of the components (e.g., via friction and/orcorrosion). In addition to particulates and other environment-relatedcontaminants, environmental conditions within the enclosure may affectlife span of electronic and/or mechanical components housed therein. Forinstance, relative humidity (RH) within an enclosure of a disk drive mayaffect the performance and reliability of the head/disk interfaces(HDI), which can be important for the magnetic recording process. Forexample, head-to-disk stiction and media corrosion are aggravated byhigh relative humidity levels. As another example, excessive disk wearand electrostatic discharge may occur at very low relative humiditylevels. Accordingly, various embodiments are directed to addressingthese issues as relate to electronic and/or mechanical components, usinga package having a desiccant that absorbs (or has absorbed) apredetermined amount of liquid therein.

In some embodiments, an apparatus includes an environmental controlmodule configured to regulate relative humidity within an enclosure. Theenvironmental control module includes a desiccant material containedwithin a package. The desiccant material absorbs and releases watervapor according to a humidity level in the environment relative to amoisture level of the desiccant material. By charging the desiccantmaterial to a specific moisture level, the environmental control modulemay be configured to set and maintain relative humidity in an enclosureto a target relative humidity.

In some embodiments, a moisture level is set and/or moisture is removedfrom an environmental control module and/or desiccant material therein,prior to adding a predetermined amount of moisture. This approach can beused to set an amount of moisture added to such a module, using abaseline amount of moisture known to be present in the module. Forinstance, the module may be dried such that negligible moisture ispresent, prior to adding a predetermined amount of liquid. Moisture maybe extracted, for example, by increasing temperature (e.g., in an oven)and/or decreasing atmospheric pressure (e.g., in a vacuum chamber) toevaporate liquid and expand water vapor trapped in the environmentalcontrol module. Liquid may remain, for example, in crevices of theenvironmental control module following manufacturing processes thatutilize liquids (e.g., for washing or etching components). Theevaporated liquid escapes from the environmental control module throughan opening that remains uncovered during the extraction process. Theextraction processes remove substantially all moisture from theenvironmental control module. Because substantially all moisture isremoved, multiple environmental control modules may be set to baselinemoisture level (e.g., 0%, or less than about 5%), regardless of theoriginal moisture content of the environmental control modules. In thismanner, variability of moisture levels resulting from variation inmanufacturing processes may be removed.

After removing moisture from the environmental control module, liquid isdeposited inside the environmental control module. This may beaccomplished, for example, by depositing liquid via an opening in apackage of the environmental control module, or injecting moisture usingan approach that generally maintains the package in a sealed condition(e.g., by injecting by way of a needle extending through a membrane thatre-seals upon removal of the needle). A seal is placed over the openingto contain the liquid water within the environmental control module. Thedesiccant material absorbs vapor resulting from evaporation of theliquid within the package. In this manner, the desiccant material may beset to a desired moisture content with high accuracy. An amount ofmoisture in the package can be increased by injecting additional liquid,to suit particular implementations.

In some embodiments, the environmental control module is placed in anenclosure with electrical and/or mechanical components, and theenclosure is closed (e.g., sealed). The seal over the opening in theenvironmental control module includes, or may be made to include, achannel for transfer of water vapor (or other gaseous material) into andout of the environmental control module. The channel allows water vaporreleased from the desiccant material to transfer to the enclosure and/orexcess water vapor in the enclosure to be absorbed by the desiccantmaterial. In some implementations, the desiccant material is configuredwith a moisture level sufficient to maintain a desired relative humidityin an enclosure over a period (e.g., a number of years), over whichmoisture may escape from the enclosure. As one example, it has beendetermined that lifespan of components in a hard disk drive may beenhanced by maintaining relative humidity in an enclosure of the harddrive within a range of 6% to 15%. In some embodiments, the desiccantmaterial is configured to have a moisture level sufficient to maintain adesired relative humidity in an enclosure to 10%+/−4% (e.g., over a settime period).

The amount of liquid water required to be added to the environmentalcontrol module to set the desiccant material to a moisture levelsufficient to maintain a desired relative humidity may be determinedusing various processes. The amount of liquid water may be determined,for example, using a look-up table indicating respective amountscorresponding to a plurality of relative humidity levels for a specificamount of desiccant material and enclosure volume.

The environmental control module may include various materials to absorband/or release water vapor or various other elements (e.g., volatileorganic vapor contaminates). Materials for absorption may include, forexample, silica gel A, activated carbons, chemical getters, chemicalacid buffers, bicarbonates and polymers such as polyacrylic acid (PAA)or polyacrylamide (PAM), and various combinations thereof.

Various embodiments are directed to methods involving setting a moisturelevel within a desiccant such as discussed above (e.g., drying thedesiccant by heating), and adding liquid/moisture to the desiccant inorder to set a specific level of moisture therein. For instance, aboutall liquid can be removed, such that a resulting moisture level is setvia the amount of liquid added after drying. The desiccant is sealedwithin a package and, upon opening of the package (e.g., puncturing of aseal or wall of the package), operates to facilitate the exchange ofmoisture with an environment in which the package resides. In someimplementations, the amount of the desiccant material is set to absorb afirst amount of the liquid, which is deposited therein, and is set toprovide a specified relative humidity for a predefined enclosure volume.

In some implementations, an opening such as a channel is provided orformed in the package. The opening is arranged in size and location toprovide restricted transfer of moisture between the package and anenvironment in which the package resides. The opening is sealed, whichseals the desiccant and liquid within the package (with the liquid beingadded before and/or after sealing). Once the package is in place, theseal can be re-opened to allow moisture transfer as discussed herein. Insome embodiments, a membrane is placed between the desiccant materialand the opening, and transfers moisture therebetween.

In certain embodiments, the liquid and the desiccant are sealed withinthe package by applying a structural component having a channel operableto transfer moisture at a restricted rate and exposed to an environmentin the package that includes the desiccant. A sealing component sealsthe channel, and in response to being altered (e.g., punctured orotherwise having a portion thereof removed), provides an opening intothe channel that couples the environment in the package with anenvironment external to the package.

The desiccant material is used to maintain relative humidity in anenclosure for a variety of approaches. For instance, relative humiditymay be maintained within a target range by absorbing additional watervapor in response to relative humidity in the enclosure exceeding thetarget range, and releasing water vapor in response to relative humidityin the enclosure falling below the target range.

Various embodiments are directed to controlling moisture for a circuitcomponent sealed within an enclosure. A package or environmental controlmodule as discussed herein is sealed with the circuit component. Anopening is provided in the package, before or after sealing the opening,and the desiccant material and vapor absorbed therein is used to set amoisture level in the enclosure via the provided opening. The circuitcomponent may include non-volatile memory, or be provided as part of ahard disk drive (e.g., having hard disk-drive disk, a head-actuationassembly, and a motor in the enclosure, in which the head-actuationassembly and the motor read and write data on the disk).

Other embodiments are directed to an apparatus, as may be implementedconsistent with methods as characterized herein. In one or more suchembodiments, an apparatus includes a package, a desiccant material andliquid contained within the package, and a seal that seals the liquidand desiccant material in the package. The seal (e.g., a material and anadhesive that adheres to an external or other surface of the package)operates with the package, desiccant material and liquid to, uponopening of a passage through the seal, maintain a humidity level withinan enclosure environment in which the package resides. For instance,humid gas may be passed between an interior region of the package and anenclosure environment in which the package resides, via the passage. Insome implementations, the humidity level is maintained level by passinghumid gas, which carries a portion of the liquid from within thepackage, from the package to the enclosure environment. Otherimplementations involve passing humid gas into the package from such anenclosure. In certain implementations, a membrane separates thedesiccant material from the passage, and transfers moisture between thedesiccant material and the passage.

In various embodiments, the apparatus includes a channel in the package,which has an opening extending from an environment within the package toan external surface of the package. The seal operates to seal thechannel until the seal is altered (e.g., removed or punctured). Thechannel may, for example, be implemented to provide restricted transferof moisture between the environment within the package and anenvironment in which the package resides, upon opening of the passage.

In some implementations, the seal includes a structural component havinga channel that transfers moisture at a restricted rate, from or to anenvironment in the package including the desiccant. A sealing componentinitially seals the channel, and upon alteration (e.g., puncture orremoval) provides an opening into the channel, therein coupling theenvironment in the package with an environment external to the package.

The package and desiccant can be implemented in a variety of manners. Insome embodiments, the desiccant absorbs the liquid and, via the packageand the seal, maintains relative humidity in an enclosure in which thepackage resides. Water vapor is absorbed as relative humidity in theenclosure exceeds a target range, and released as relative humidity inthe enclosure falls below the target range.

In accordance with one or more embodiments, an apparatus having apackage (and related environmental control module as applicable) furtherincludes a sealed enclosure in which the package resides. The packageand enclosure provide transfer of humid gas between an environmentwithin the package and an environment within the enclosure (and externalto the package). The desiccant material may, for example, absorb theliquid and provide a specified relative humidity within the sealedenclosure, by releasing the absorbed liquid via the passage.

In some embodiments, the apparatus includes a tool that operates toremove, break, or puncture the seal, or otherwise form an openingtherein. The tool may, for example, be sealed within the enclosure andoperate to provide an opening in the seal after the enclosure is sealed.This approach can provide for the exchange of a predetermined amount ofhumid gas from within the package to the environment within theenclosure.

An enclosure as referred to above can be used for a variety ofapproaches, such as to enclose a circuit or other component. In certainimplementations, the enclosure is a hard disk drive enclosure having ahard disk-drive disk, a head-actuation assembly, and a motor. Thehead-actuation assembly and the motor operate to read and write data onthe disk.

Packages or environmental control modules as characterized herein may beused to control moisture and/or other environmental parameters inenclosures of various mechanical and/or or electrical devices. For easeof explanation, the examples may be primarily described with referenceto regulation of moisture in an enclosure housing a non-volatile memorysuch as a hard disk drive. However, such embodiments are applicable toimplementation with a multitude of circuits, mechanical components andother items in various types of environments.

Turning now to the figures, FIG. 1 shows a process for configuring anenvironment control module structure, consistent with various aspects ofthe present disclosure. At block 102, moisture is extracted from anenvironmental control module. As previously indicated moisture may beextracted, for example, by increasing temperature (e.g., in an oven)and/or decreasing atmospheric pressure (e.g., in a vacuum chamber) toevaporate liquid and expand water vapor trapped in the environmentalcontrol module. Optionally, in some implementations, a seal may beplaced over the opening in an environmental control module to maintainthe desiccant material at the baseline moisture level for an extendedperiod.

At block 104, an amount of liquid such as water to be added to thedesiccant material to provide a desired relative humidity is determined.The amount of liquid may depend on the desired relative humidity level,the amount of desiccant material, and a volume of an enclosure to beregulated at the desired relative humidity level. The amount of liquidmay be determined, for example, using a look-up table indicatingrespective amounts corresponding to a plurality of relative humiditylevels for a specific amount of desiccant material and enclosure volume.At block 106, the determined amount of liquid is deposited in theenvironmental control module via the opening. At block 108, a seal isplaced over the opening to contain the liquid within the environmentalcontrol module. As the liquid evaporates, it is absorbed by thedesiccant material. In this manner, the desiccant material may be set toa desired moisture content with high accuracy. In some implementations,the liquid is heated prior to being deposited at block 106 to increasethe rate of evaporation. The resulting environmental control module maythen be immediately implemented with circuitry or other components in anenclosure or other environment, or otherwise provided as a separatemodule that may be implemented at a later time (e.g., shipped from afacility that manufactures the environmental control module to variousentities that subsequently employ the modules with enclosures, such asby forming an opening in the module and placing the module in anenclosure).

In some embodiments, the method continues at block 110, at which theenvironmental control module is placed in the enclosure with electricaland/or mechanical components and the enclosure is closed. An opening ismade in the environmental control module, which can be carried out priorto or after the environmental control module is sealed in the enclosure.This opening facilitates passage of moisture between the environmentalcontrol module and the enclosure (e.g., until an equilibrium-type stateis achieved). Over time, moisture may be further passed in this context,such as after moisture in the enclosure escapes, which can be useful forensuring that a set amount of moisture remains in the enclosure.

In some implementations, the seal placed over the opening includes achannel configured to transfer water vapor (or other gaseous material)in and out of the environmental control module. The channel allows watervapor released from the desiccant material to transfer to the enclosureand thereby provide and maintain a desired relative humidity in theenclosure. Conversely, the channel allows excess water vapor in theenclosure to be absorbed by the desiccant material.

In some implementations, the channel in the seal is initially absent orclosed. This allows the set moisture of the desiccant material to bemaintained for an extended period before the environmental controlmodule is placed into service. The channel may be initially closed by anon-permeable layer (e.g., a layer of foil) in the seal or a temporarylayer placed over the channel. If the channel is initially closed orabsent, the channel may be opened or formed prior to closing theenclosure. An opening may be formed in the seal, for example, bypenetrating a non-permeable layer in the seal.

In some implementations, the enclosure may also be filled with an inertgas prior to closing the enclosure. In some implementations, the fillingof the enclosure with the inert gas may additionally serve to initiallyremove water vapor from the enclosure or set water vapor content to theenvironment to an initial value.

In some implementations, the channel may be formed or opened at a latertime after the enclosure is closed. For example, in someimplementations, the enclosure includes an electromechanical deviceconfigured to pierce a hole in the seal in response to electronicsignal. In other implementations, the enclosure may include a hole for auser to manually insert a tool to pierce the seal of the environmentalcontrol module. The hole may also be used to inject an inert gas intothe enclosure. After piercing the seal, an external seal may be placedover hole to close the enclosure and allow the environmental controlmodule to regulate the relative humidity.

In some embodiments, multiple environmental control modules may beplaced in an enclosure. The seals of the environmental control modulesmay be punctured, for example, at different times to extend the lengthof time at which the desired relative humidity may be maintained. Insome implementations the enclosure may include a mechanical deviceconfigured to automatically puncture seals of environmental controlmodules at regular service intervals to maintain proper operation. Inother implementations, seals of environmental control modules may bemanually punctured by a user at regular service intervals to maintainproper operation of the device. For example, seals of environmentalcontrol modules may be punctured at regular service intervals indicatedby terms of a warranty agreement for an apparatus.

FIG. 2 shows a cross-sectional side view illustrating an environmentcontrol module structure, consistent with various aspects of the presentdisclosure. The environmental control module includes a body 210 that isfilled with a desiccant material 208. The body 210 may be a deformablematerial, such as a plastic-sealed bag, or a non-deformable materialsuch as a metal housing. A membrane 206 covers the desiccant material208. The desiccant material is configured to absorb and release watervapor to maintain a certain relative humidity in a substantially closedenvironment. Alternatively or additionally, the material 208 may includematerials configured to regulate various other contaminants. Forexample, in some implementations, the material 208 may include amaterial configured to trap oxygen in an environment, to reduce theoxidation rate of copper wiring. The membrane 206 prevents the desiccantmaterial 208 from escaping the body 210. The membrane 206 is configuredto allow moisture to transfer to and from the desiccant material 208. Apackage lid 204 is configured to mate with the body 210 to form anenclosure for the desiccant material 208 and the membrane 206. Thepackage lid 204 includes an opening 202 for moisture and/or regulatedelements to enter and exit the environmental control module. Aspreviously described, after removing moisture from the environmentalcontrol module, the desiccant material 208 may be charged by depositingan amount of liquid water or regulated contaminants via the opening 202in the lid 204. As previously indicated, after depositing the liquid,via the opening, a seal is placed over the opening 202 to contain theadded liquid within the environmental control module.

FIG. 3 shows a cross-sectional side view illustrating the environmentalcontrol module of FIG. 2 with a seal 302 placed over the opening 202 inthe lid 204. The seal 302 includes a channel 304 configured to transferwater vapor (or other gaseous material) in and out of the environmentalcontrol module. The size of the channel may be configured to control arate at which water vapor is transferred in and out of the environmentalcontrol module. In some implementations, the channel 304 is initiallyabsent from the seal 302 or closed, thereby allowing a set moisturecharge of the desiccant material to be maintained for an extended periodbefore the environmental control module is placed into service. Asdescribed in more detail with reference to FIG. 8, a channel may beformed in a seal by piercing one or more layers of the seal to create ahole.

FIG. 4 shows a cross-sectional side view illustrating an exampleapparatus, consistent with various aspects of the present disclosure. Inthis example, the apparatus includes a sealed enclosure 402 containingone or more electronic and/or mechanical components 406 along with anenvironmental control module 404. As described with reference to FIGS.1, 2, and 3, the environmental control module 404 includes a desiccantmaterial that has been initialized to a moisture content level (e.g.,using the process shown in FIG. 1) that is sufficient to maintain adesired relative humidity within the enclosure 402. The environmentalcontrol module 404 also includes a seal having a channel configured totransfer water vapor or other gaseous materials into and out of theenvironmental control module 404. When the relative humidity is too lowin the enclosure 402, water vapor is released from the desiccantmaterial in the environmental control module 404 and provided to theenclosure via the channel in the seal. Conversely, when the relativehumidity is too high in the enclosure 402, water vapor is removed fromthe environment of the enclosure via the channel in the seal andabsorbed by the desiccant material in the environmental control module404.

In some embodiments, the apparatus shown in FIG. 4 includes a tool 409operable to generate an opening in a seal 405. By way of example, thetool 409 is shown with a needle-like structure, but can be implementedwith a variety of different structures that operate to provide anopening in the seal 405. In some implementations, a movable structure408, such as a diaphragm-type structure, operates to move the tool 409into contact with the seal 405. In certain implementations, the movablestructure 408 is integrated with an external sidewall and operable foractuation by an external force, after the apparatus has been sealed. Inother implementations, the tool 409 operates to provide an opening inthe seal after the apparatus has been sealed, and without interaction byan external force.

As previously indicated, the moisture content of the desiccant materialmay be set to different levels to adjust the relative humidity levelthat is maintained by the environmental control unit. FIG. 5 shows agraph of relative humidity in an enclosure maintained by environmentalcontrol modules over time when charged with various initial moisturelevels, consistent with various aspects of the present disclosure. Inthis example, the graph includes respective plots 502 and 504 for twoinitial moisture levels. A first plot 502 shows relative humiditymaintained by an environmental control module having desiccant materialwith the baseline moisture level (e.g., 0%). At this moisture level, thedesiccant material decreases relative humidity in an enclosedenvironment from approximately 40% to 0% in nearly 15 hours. The secondplot 504 shows relative humidity maintained by an environmental controlmodule having desiccant material initially charged with 60 μL of water.At this moisture level, the desiccant material decreases relativehumidity in an enclosed environment from approximately 25% to 9% inapproximately 40 hours. Thereafter, the relative humidity is maintainedat this level. Thereafter, the desiccant material maintains the relativehumidity at a nearly constant level. The relative humidity may beincreased, relative to plot 504, by increasing the initial moisturelevel of the desiccant material (e.g., by depositing greater than 60 μLof water). Conversely, the relative humidity may be decreased, relativeto plot 504, by decreasing the initial moisture level of the desiccantmaterial (e.g., by depositing less than 60 μL of water).

FIG. 6 shows a graph of water absorption by percentage of weight forvarious materials at different relative humidity levels. In thisexample, the graph includes 6 plots charting the water absorption forrespective material samples. Plots 602 and 606 show water absorption bypercentage of weight for respective samples of silica gel A. Plots 610and 612 show water absorption by percentage of weight for respectivesamples of carbon-32. Plots 604 and 608 show water absorption bypercentage of weight for respective samples of a mix of silica gel A andcarbon-32.

FIG. 7 shows a partial exploded perspective view of an exampleenvironmental control module, consistent with various aspects of thepresent disclosure. The environmental control module includes a body 702that is filled with a desiccant material 704. A membrane 706 covers thedesiccant material 704. The membrane 706 contains the desiccant material704 within the body 702 and is configured to allow moisture to transferto and from the desiccant material 704. A package lid 708 is configuredto mate with the body 702 to form an enclosure for the desiccantmaterial 704 and the membrane 706. The package lid 708 includes anopening for moisture and/or regulated elements to enter and exit theenvironmental control module. As previously described, after removingmoisture from the environmental control module, the desiccant material704 may be charged by depositing an amount of liquid water or regulatedelement via the opening in the lid 708. After depositing the liquid, viathe opening, a seal 710 is placed over the opening in the lid 708.

Various types of seals may be used to cover the opening in the lid ofthe environmental control module. FIG. 8 shows a partial explodedperspective view of an example seal for use with an environmentalcontrol module, consistent with various aspects of the presentdisclosure. In this example, the seal 800 includes a membrane structure802 (e.g., a polytetrafluoroethylene membrane) having a bottom lipconfigured to mate against a lid of environmental control module (e.g.,lid 708 in FIG. 7). Foam wedges 806 are affixed inside the membranestructure 802 by a two-sided adhesive layer 804. In this example, a foilmoisture barrier seal 810 is affixed to the bottom of the membranestructure 802 by a two-sided adhesive layer 808. Another two-sidedadhesive layer 812 is affixed to the bottom of the foil moisture barrierseal 810. The two-sided adhesive layer 812 can be used to affix the seal800 to a lid of an environmental control module to cover an opening inthe lid.

A channel may be formed in the seal 800 by puncturing a small diameterhole in the foil moisture barrier seal 810. The channel is configured totransfer moisture (or other regulated material) in or out of anenvironmental control module. The foil moisture barrier seal 810 allowsa desiccant material in the environmental control module to bemaintained at an initial moisture charge until it is installed in anenclosure within which environmental conditions are to be regulated.

FIGS. 9A, 9B, 10A, and 10B show perspective and cross-sectional views ofthe environmental control module of FIG. 7 with sealed and unsealedopenings. FIG. 9A shows a perspective view of the environmental controlmodule of FIG. 7 with an unsealed opening. FIG. 9B shows cross-section Iof the environmental control module of FIG. 9A. FIG. 10A shows aperspective view of the environmental control module of FIG. 7 with anopening covered using the seal shown in FIG. 8. FIG. 10B showscross-section II of the environmental control module of FIG. 10A.

FIG. 11 shows a partial exploded perspective view illustrating a diskdrive apparatus having an environmental control module, consistent withvarious aspects of the present disclosure. The disk drive apparatusincludes an enclosure 1105 housing a media disk 1130 that stores data.The apparatus includes an actuator arm 1140 in the enclosure 1105. Theactuator arm 1140 is configured to read data from and write data to themedia disk 1130. The apparatus includes a motor 1160 within theenclosure 1105 that is configured to control the speed at which themedia disk 1130 is rotated in the process of reading and writing data bythe actuator arm 1140.

An environmental control unit 1110 is also mounted inside the enclosure1105. The environmental control unit 1110 contains a desiccant materialcharged with an amount of liquid via an opening, as described above. Theopening is covered by seal 1125. As previously indicated, in someimplementations, the seal 1125 includes a pre-formed channel 1120 fortransfer of gaseous material (e.g., water vapor) into or out of theenvironmental control module 1110 at a controlled rate. In some otherimplementations, the channel 1120 may not be present in the seal 1125initially, or may initially be closed to prevent transfer of the gaseousmaterial. The channel 1120 may be created or opened by puncturing adesignated portion of the seal 1125. As an option and consistent withcertain specific embodiments discussed above, a portion of the seal 1125configured to form the channel 1120 when punctured can be aligned withan access port (not shown) of the enclosure 1105. A puncture tool may beused to pierce the seal through the aligned access port to create achannel in the seal for transfer of vapor at a controlled rate.

Various blocks, modules or other circuits may be implemented to carryout one or more of the operations and activities described herein and/orshown in the figures. In these contexts, a “block” (also sometimes“logic circuitry” or “module”) is a circuit that carries out one or moreof these or related operations/activities (e.g., determining an amountof liquid for a desired relative humidity, or controlling machinery forconfiguring moisture level of an environmental control module). Forexample, in certain of the above-discussed embodiments, one or moremodules are discrete logic circuits or programmable logic circuitsconfigured and arranged for implementing these operations/activities Incertain embodiments, such a programmable circuit is one or more computercircuits programmed to execute a set (or sets) of instructions (and/orconfiguration data). The instructions (and/or configuration data) can bein the form of firmware or software stored in and accessible from amemory (circuit). As an example, first and second modules include acombination of a CPU hardware-based circuit and a set of instructions inthe form of firmware, where the first module includes a first CPUhardware circuit with one set of instructions and the second moduleincludes a second CPU hardware circuit with another set of instructions.

Based upon the above discussion and illustrations, those skilled in theart will readily recognize that various modifications and changes may bemade to the various embodiments without strictly following the exemplaryembodiments and applications illustrated and described herein. Forexample, though aspects and features may in some cases be described inindividual figures, it will be appreciated that features from one figurecan be combined with features of another figure even though thecombination is not explicitly shown or explicitly described as acombination. Furthermore, various features of the different embodimentsmay be implemented in various combinations. Such modifications do notdepart from the true spirit and scope of various aspects of theinvention, including aspects set forth in the claims.

What is claimed is:
 1. A method comprising: removing moisture from anenvironmental control module including a desiccant material containedwithin a package; depositing a liquid inside the package; and sealingthe liquid and the desiccant material within the package.
 2. A method asin claim 1, further including setting an amount of the desiccantmaterial in the environmental control module to absorb a first amount ofthe liquid; and wherein depositing the liquid includes depositing anamount of liquid sufficient to provide a specified relative humidity fora predefined enclosure volume upon absorption of the first amount of theliquid.
 3. A method as in claim 1, wherein removing the moisture fromthe environmental control module includes drying the desiccant materialand therein removing about all liquid from the desiccant material.
 4. Amethod as in claim 1, further including providing a channel in thepackage, by configuring and arranging the channel to provide restrictedtransfer of moisture between the package and an environment in which thepackage resides.
 5. A method as in claim 1, further including providingan opening in the package, and providing a membrane that separates thedesiccant material from the opening and that is configured and arrangedto transfer moisture between the desiccant material and the opening. 6.A method as in claim 1, wherein sealing the liquid and the desiccantmaterial within the package includes applying a structural componenthaving a channel configured to transfer moisture at a restricted rate,the channel being exposed to an environment in the package including thedesiccant material; and a sealing component that seals the channel, thesealing component being configured and arranged to, in response to aportion thereof being altered, provide an opening into the channel andtherein couple the environment in the package with an environmentexternal to the package via the channel.
 7. A method as in claim 1,further including, after sealing the liquid and the desiccant materialwithin the package, sealing the environmental control module in anenclosure; and using the desiccant material to maintain relativehumidity in the enclosure within a target range by absorbing additionalwater vapor in response to relative humidity in the enclosure exceedingthe target range, and releasing water vapor in response to relativehumidity in the enclosure falling below the target range.
 8. A method asin claim 1, wherein removing the moisture includes placing theenvironmental control module in a vacuum chamber.
 9. A method as inclaim 1, wherein removing the moisture includes heating theenvironmental control module.
 10. A method of claim 1, whereindepositing a liquid inside the package includes depositing the liquidvia an opening in the package; and sealing the liquid and the desiccantmaterial within the package includes sealing the opening in the package.11. A method as in claim 10, wherein sealing the liquid and thedesiccant material within the package includes placing an adhesive sealover the opening.
 12. A method as in claim 10, further including aftersealing the opening in the package, providing an opening in the package;and using the desiccant material and vapor absorbed therein to set amoisture level in an environment in which the package resides, via theprovided opening.
 13. A method as in claim 10, further including sealinga circuit component and the environmental control module within anenclosure; after sealing the opening in the package, providing anopening in the package; and using the desiccant material and vaporabsorbed therein to set a moisture level in the enclosure, via theprovided opening.
 14. A method as in claim 13, wherein the circuitcomponent includes a non-volatile memory.
 15. A method as in claim 13,wherein the circuit component includes a hard disk-drive disk, ahead-actuation assembly, and a motor in the enclosure, thehead-actuation assembly and the motor being configured and arranged toread and write data on the disk.
 16. A method of claim 1, furtherincluding using the desiccant material to absorb vapor resulting fromevaporation of the liquid within the package.
 17. A method of claim 1,wherein depositing the liquid includes depositing an amount of liquidbased on characteristics of the desiccant material and a target relativehumidity for an enclosure volume in which the package is to be placed.18. A method of claim 1, further including sealing the package afterremoving the moisture therefrom, wherein depositing a liquid inside thepackage includes injecting the liquid into the sealed package, andwherein sealing the liquid and desiccant material in the packageincludes using characteristics of a portion of the package via which theliquid is injected to re-seal the desiccant material after the liquid isinjected into the package.
 19. A method of claim 1, wherein sealing theliquid and the desiccant material within the package includes: formingthe package with a channel opening extending from an interior region ofthe package to an outer surface of the package, and sealing a portion ofthe channel opening adjacent the outer surface.
 20. A method of claim 1,further including, after sealing the liquid and the desiccant materialwithin the package, modifying an amount of liquid in the package basedon an intended implementation of the package with a circuit component ina sealed enclosure.